This invention relates to a steam processing apparatus and, more particularly, to an apparatus for receiving a mixture of liquid and vapor, separating the vapor from the liquid and discharging the vapor and the liquid from separate outlets.
In natural circulation vapor generators, mixtures of water and steam rise in heated steam-generating tubes and discharge into one or more large steam drums disposed in an elevated position above the tubes. The drums include means to separate the water from the steam with the latter being removed through openings of the upper portions of the drum and the former being recirculated through downcomers to the boiler and back to the steam generating tubes to complete the natural circulation loop.
In relatively large installations employing natural circulation vapor generators, it is essential that an efficient separation of the steam from the water be effected in the drum with minimal pressure loss in order to furnish steam of the required purity to the point of use, and steam-free water to the circulation system. In these arrangements, the expansion of the water-steam mixture through the separator results in a substantial pressure drop which, if too large, can adversely effect the circulation system. Also at low must have sufficient flow area to minimize pressure loss and still achieve separation.
Many of the prior art arrangements designed to minimize the pressure drop and maximize the flow area have included a drum with an extraordinarily large length which is incompatible from a fabrication standpoint with the furnace width dimension for a given capacity unit. As a result, the drum often overhangs relative to the furnace which tends to increase material and erection costs.